The present invention relates to a method and apparatus for injecting hydrogen within an engine. In particular, the invention relates to injecting hydrogen within an engine of a vehicle to increase the speed of a turbocharger.
In a turbocharged engine, a turbocharger may include a compressor to compress air intake from the atmosphere or an exhaust gas recirculation (EGR) system, to be delivered to the engine for combustion. By increasing the mass of air entering the engine, the expansive power of combusted energy is increased resulting in increased available torque and thus power and efficiency.
A compressor may be coupled to a high speed turbine within the exhaust system. A turbine may convert the kinetic energy and the potential energy from pressure into work that may be delivered to the compressor to provide power.
Boost from a turbocharger may be responsive to operating conditions and may be initiated to achieve acceleration. The initiation of turbocharge may be referred to as turbo boost. In systems that initiate turbo boost in response to throttle change, achieving boost requires first initiating the energy conversion capabilities of the turbine, accumulating of an amount of work, delivering accumulated work to the compressor, compressing intake aircharge, then delivering compressed air intake to the engine for combustion. The delay between throttle actuation and combustion of boosted aircharge to the engine is called turbo lag.
Turbo lag may be perceived by the operator as hesitation in the throttle response when accelerating from an idle speed. Turbo lag decreases the responsiveness of the vehicle to the operator and thus driving comfort and control.
Turbo lag may be compounded by the increased specific power demands of newer engines. Greater power demands rely on a greater volume of compressed air to be delivered to the engine during turbo boost. To compress an increased volume of air, the amount of work delivered to the compressor from the turbine must similarly increase. However, the accumulation of the increased amount of work requires time, thus more time elapses between turbo boost and throttle actuation, increasing turbo lag.
Various solutions have been devised to address increased turbo lag. For a diesel engine, the two most common approaches are to use a variable nozzle turbine (VNT) or a twin turbocharger in which one large turbocharger is used for power and one small turbocharger is used for heightened responsiveness. However, these solutions are bulky, costly and challenging to control.
Hydrogen injection has been used to improve engine performance. For instance US 20100043730, in the name of O'Bireck, describes a hydrogen generating system for an engine with a turbocharger to generate extra power during a turbo boost. O'Bireck discloses delivering the hydrogen to the fuel system for mixing with engine fuel. This, however, does not provide a means of reducing turbo lag.
The inventers found that by including a hydrogen delivery apparatus adapted to deliver hydrogen to the exhaust gas system such that the hydrogen can combust and expand, turbine speed may increase and turbo lag decrease. Further, by delivering hydrogen to the exhaust system upstream of the turbine where exhaust gas is relatively oxygen rich, the combustion of hydrogen may be assisted.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.